Effects of dietary protein levels on production performance and serum insulin-like growth factor-1 levels in sika deer

Abstract

The purpose of this study was to investigate the influence of dietary protein levels on the performance of sika deer. Twenty-four male sika deer were randomly assigned into three treatments, where they were fed a diet containing either 12, 16 or 20% crude protein (CP). During the antler growth period the average bodyweight gain in 12, 16 and 20% CP levels was 17.3, 19.9 and 14.4 kg, respectively; antler yield was 2224, 2518 and 2246 g, respectively. A significant positive relationship (P < 0.01) was found between serum insulin-like growth factor (IGF)-I concentration and bodyweight gain (P < 0.01) and antler yield (P < 0.01), using the regression equations: bodyweight gain (kg) = 0.06IGF-1 (ng/mL) – 52.14 (R2 = 0.69, n = 8) and antler yield (g) = 3.55IGF-1 (ng/mL) – 1659.4 (R2 = 0.77, n = 8), respectively. We concluded that 16% dietary protein was optimal for bodyweight gain and antler yield during the antler growth period in the sika deer.